Production of polymeric compounds



Patented Jan. 1, 1946 PRODUCTION OF POLYMERIC COMPOUNDS Henry Dreyfus,London, England; Claude Bonard administrator of said Henry Dreyfus, de-

ceased No Drawing. Application November 21, 1942, Se-

rial No. 466,478. In Great Britain January 23,

11 Claims.

This invention is concerned with improvements in the production ofhighly polymeric compounds and of artificial filaments, films and otherproducts therefrom, and is a continuation in part of my application S.No. 316,367 filed January 30, 1940.

In recent years a great deal of research has been directed to theproduction from simple organic compounds of polymeric compounds of highmolecular weight having properties which render them suitable for theproduction of filaments, films, coating compositions and other articlesfor which naturally occurring substances, such as resins or cellulose,and semi-synthetic substances such as cellulose derivatives havepreviously been employed. Usually the polymers are obtained either bycausing the union of a number of unsaturated molecules containing theethylene linkage by intermolecular linkage at the double bonds, as inthe case of polyvinyl compounds, or by a condensation process in whichmolecules containing two reactive radicles unite together with theelimination of water or other by-product. Polyamides are well-knownexamples of this type of polymer.

According to the present invention condensation polymers of highmolecular weight suitable for the production of filaments, films,coating compositions and other articles are produced by heating apolymer-forming reaction mixture comprising an organic compoundcontaining two reactive radicles of which one is the radicle of urea ora similar compound, e. g. N.N'-dimethylurea or N-methyl-thiourea, andhas the formula where R and R1 are each a hydrogen atom or a hydrocarbonradicle and X is an oxygen or sulphur atom and the other either has thesame general formula or is an amino radicle. When a compound containingtwo radicles having the general formula ise lTployedrthetwoi-adicles maybe the same or diflerent. For instance, one may be a urea radicle andthe other a thiourea. radicle.

Various methods are available for theproduction of the di-ureas,amino-ureas and similar compounds which may be employed as startingmaterials. For instance, a di-urea may be produced by reacting twomolecules of ureawith one molecule of a dihalogenated paramn, e. g. 1.6-dibromhexane, to give a straight chain compound having a urea radicle ateach end or it may be produced by reacting one molecule of a diamine, e.g. LIO-diamino-decane, with two molecules of carbamyl chloride.Amino-ureas may be produced in a similar manner by the use ofappropriate proportions of the reagents. Similar methods may be employedfor the production of the thiourea derivatives and similar derivativesemployed in the present process.

Another method which may be employed successfully is based onthereaction between diamines and isocyanates and the like. For example,amino-urea'sor di-ureas may be produced by reacting diaminehydrochlorides with appropriate proportions of metal isocyanates, whileif metal isothiocyanates are employed thiourea derivativesmay beproduced. Compounds containing substituted urea or thiourea radicles maybe produced in a similar manner using esters of isocyanates orisothiocyanates. For example, two mols of methyl or ethyl isocyanate orisothiocyanate may be reacted with one mol of a diamine to form thecorresponding alkylated urea or thiourea. Production of a polymer may becarried out directly after formation of a di-urea or similar compound,without separation of the compound, by subjecting the reaction mixture,after the addition of further reagent if required, to polymer-formingconditions. Usually however,-it is preferable to separate and purify thecompound, particularly when it is produced from a metal isocyanate orisothiocyanate, on account of the by-product formed.

Production of the polymers according to the present invention may beeffected by reacting a di-urea or similar compound with itself, withanother compound of the same type or with a diamine, or by reacting anamino-urea with itself or with a similar compound. Linking up ofindividual molecules to give the macromolecules present in the polymersis thus the result of reaction between pairs of radicles or betweenradicles and amino radicles. The first type of reaction probably resultsin the production 0! polymers containing biuret or similar residues andthe second type of polymers containing urea or similar residues.Polymers containing both types of residues may be obtained, e. g. byusing diamines and di-ureas or the like in other than equimolecularproportions.

When a reagent or reagents containing amino groups is employed theproportion of amino groups to urea groups or the like in the reactionmixture should not greatly exceed 1:1, since otherwise it may not bepossible to obtain a poigmer of an average molecular weight suilicientlyhigh to give the desired properties by reason of all the urea groups orthe like having been used up in the formation of low polymers havingamino groups at each end. For instance. to take an extreme case, withtwo mols of a diamine to one mol of a di-urea the average composition ofthe product will be which is not capable of further polymerisation Onthe other hand an excess of urea or similar groups over the 1:1 ratio isnot objectionable, since these groups can react with each other to formbi-uret or similar residues.

The reagents em loyed should not be such that they are ca able ofreacting to form cyclic compounds containing less than eight atoms.particularly 4-7 atoms, in the ring. as if they are, such a react on isliable to occur to the detriment of polymer formation. For example whenan amino-urea or the like is employed the amino group and the radicle ofurea or the like should be separated by a chain of at least five atoms.

The compounds employed in the present process are preferably aliphaticcompounds, particularly ones in which the pairs of reactive radicles arelinked by chains of methylene groups or are at least attached tomethylene groups. Examples of suitable compounds have been given above.Others which may be employed are 1.3-

diamino-propane, 1.4-diamino-butane and 1.5- diamino-pentane and themonoand di-ureas and similar compounds which may be obtained from suchdiamines by th methods described above. The process is not howeverlimited to the use of such compounds. For instance, aliphatic compoundsmay be employed in which the reactive radicles are linked by chains ofatoms containing other atoms as well as carbon atoms. e. g. oxygen,sulphur or nitrogen atoms, or having alkyl or other non-reactive groupsattached to the main chain. Aromatic compounds containing the reactiveradicles may also be used. Examples of such compounds are2.2'-diamino-diethyl ether, 2.2'-diamino-diethyl sulphide andbis(2-amino-ethyl) methyla'niine, diaminobenzenes, alpha,alph'a'-diaminoxylenes and the urea and similar derivatives obtainable therefrom.

As stated above, it is preferable to employ aliphatic compounds in whichthe reactive radicles are linked by methylene groups. Such compoundsusually give polymers of higher melting points than those of polymersobtained from similar compounds containing other atoms in the chainbetween the reactive radicles or from aromatic compounds containing suchradicles. Moreover, polymers obtained from compounds containing urearadicles usually have a higher melting point than those of compoundscontaining thiourea radicles. For the production of textile fibres,therefore, for which a high melting point i desirable, it is usuallypreferable to employ aliphatic compounds containing urea radicles linkedby chains consisting of-methylene groups.

Polymers may be obtained from reaction mixtures containing otherpolymer-forming reagents as well as those characteristic of th presentinvention. For instance, they may contain aminocarboxylic acids ordicarboxylic acids, which will yield polymers containing acid amideresidues as well as bi-uret and/or urea residues or the like. Acid amideresidues usually tend to increase the melting-point, which may beadvantageous for the production of filament-forming polymers.

If polymers are produced which contain pairs of reactive radiclesfurther polymerisation may occur if the polymers are subsequently heatedto a high temperature, for instanc during a melt-spinning process. Toavoid this it may be desirable to have present in the reaction mixture asmall proportion of a "stabilising agent" i. e. a compound which canreact with one and only one of the reactive radicles. Such an agent may,for example, be a mono-alkyl halide or a secondary mono-amine.

The production of the polymeric compounds according to the process ofthe present invention is effected by heating th reactants at a suitabletemperature, for example to 250 C. or more, until a product having thedesired properties is obtained. The reaction may be carried out underatmospheric pressur or the pressure may be reduced for example to 100,50 or 5 mms. of mercury or the reaction may be carried out in amolecular still. A fairly high reaction temperature, for instanc between200 and 250 0., is usually desirable. It is desirable to removerelatively volatile by-products from the reaction medium as rapidly aspossible and this may be assisted by passing an inert gas, for examplenitrogen, through or over the reaction mixture. In any case it isadvantageous to carry out the reaction in an inert atmosphere since inthe presence of oxygen dark-coloured products may be obtained. Thereaction may be carried out in a suitable inert liquid. e. g. phenol, acresol or a xylenol, though better filamentforming products are usuallyobtained when the reaction is effected by heating the reagent orreagents alone in a molten state.

In order to obtain' products, having suitable properties for theformation of filaments, it is in general necessary to continue thereaction until the polymer has an average molecular weight of 6,000 to8,000 or 10,000 or more. Polymers of lower average molecular weight, e.g. 3,000 or 4,000, though not usually suitable for the production offilaments, may be employed for the production of films, particularlycoating films, and moulded products. in which high tenacity per unit ofcross-section is of less importance. Preferably the reaction is stoppedwhile the polymer is still soluble in suitable organic solvents, furtherpolymerisation being effected. if desirable, after the polymer has beenformed into filaments or other shaped articles.

The highly polymeric compounds of the present invention may be purifiedby washing them with suitable liquids or by dissolving them up and thenprecipitating them. They may b employed for the manufacture of shapedarticles. For example, filaments, foils and similar articles may beproduced by extruding a solution of a highly polymeric compound througha shaping device into a gaseous or liquid setting medium or by extrudinga plastic or molten mass of the polymeric substance through a shapingdevice and taking it up on a roller or other forwarding device.Filaments, films and similar products may be stretched, eithercontinuously with their production or subsequently thereto e. g. whenthey are in a softened condition under the influence 01 heat or of asuitable solvent.

The following examples illustrate the invention:

Example I 16 parts of hexamethylene diamine hydrochloride were dissolvedin about 20 parts or water and the solution diluted to about 3 times itsvolume with methyl alcohol. A concentrated aqueous solution containing13.! parts of potassium cyanate was then added and the potassiumchloride which separated out was filtered oil. The filtrate wasconcentrated by evaporation and the precipitate of di-area whichseparated on cooling was well washed with cold water to remove solublechlorides and then re-crystallised from hot water, after which it wasdried.

The di-urea was then heated at a temperature of 235-240 C. in theabsence of oxygen in an autoclave through which a current of nitrogenwas passed. Ammonia was evolved and the melt which was formed graduallyincreased in viscosity. After about two hours a solid product wasobtained melting at 245250 C. and having fibreiorming properties.

' Example II 3.4 parts of methyl isocyanate were dissolved in about 16parts of methyl alcohol and poured gradually, with continuous stirring,into about 20 parts of an alcoholic solution of 3.5 parts ofhexamethylene diamine. The solution obtained was heated to about 60 C.and then poured into an excess of cold water. The N.N'-dimethyl-di-ureawas precipitated as a white crystalline solid which was illtered'ofl,washed several times with cold water, then with acetone and finallydried.

2.3 parts of the di(methylurea) were heated at about 200 C. with 1.2parts of hexamethylene diamine in 20 parts of medium paraflin oil in theabsence of owgen in an autoclave through which a current of nitrogen waspassed. Ammonia was evolved and after about two hours a product havingfibre-forming properties was obtained. It had a melting point of about255 C.

Example III 5.05 parts of hexamethylene di-urea (obtained as describedin Example I)/ was thoroughly mixed with 1.8 parts of hexamethylenediamine (i. e. in a molecular ratio of 5 to 3) and the mixture washeated at 200 to 210 C. in the absence of oxygen in an autoclave throughwhich a current of nitrogen was passed. After about to 30 minutes aproduct having a melting point of 245-250 C. and having fibre-formingproperties was obtained.

Example IV Example V A fibre-forming polymer obtained as described inExample 111 was extruded through a jet having a diameter of .5 mm. undera nitrogen pressure of 10 lbs/sq; in. and at a temperature of 260 C. Theextruded filament was drawn down between two rollers, the second ofwhich had a peripheral speed twice that of the first, and was then takenup on a bobbin.

Having described my invention what I desire to secure by Letters Patentis:

1. Process for the production of linear polymers of high molecularweight, which comprises heating, until a polymer having film-formingproperties is obtained, a reaction mass wherein the sole polymer-formingmolecules present are molecules containing only two reactive radicleslinked by divalent organic radicles containing at least 3 and not morethan 10 chain atoms, the said reactive radicles being selected from thegroup consisting of urea, thiourea and of primary and secondary aminoradicles with urea and thiourea, and any excess in the number of aminoradicles over the number of other reactive radicles present being atmost only slight.

2. Process for the production or linear polymers of high molecularweight, which comprises heating a reaction mass wherein the sole polymerforming molecules present are molecules having the formula:

where R1, R1, R4 and Re is each selected from the class consisting ofhydrogen atom and hydrocarbon radicles, Ra is a divalent radicleconsisting of a chain containing at least 3 and not more than 10 chainatoms linking the nitrogen-containing radicles and X and X1 is eachselected from the class consisting of oxygen and sulphur atoms, heatingbeing effected at a temperature of 200 to 250", C. for at least part ofthe reaction and continued until a product having filament-formingproperties is obtained.

3. Process for the production of linear polymers of high molecularweight, which comprises heating a reaction mass wherein the solepolymerforming molecules present are molecules having the formula:

4. Process for the production of linear polymers of high molecularweight, which comprises heating a reaction mass containing hexamethylenediurea as sole polymer-forming reagent, heating being-eflected at atemperature of 200 to 250 C. for at least part of the reaction periodand continued until a product having filament-forming properties isobtained.

5. Process for the production of linear polymers of high molecularweight, which comprises heating a reaction mass containing as solepolymer-forming reagents a diamine in which each of the amino radiclescontains at least one hydrogen atom directly attached to the nitrogenatom, said amino radicles being the sole reactive radicles present inthe diamine, and an organic compound having the formula II nN.CX.NR:.R3.NR4.CX1.N R1 R where R1, R2, R4 and R5 is each selected fromthe class consisting of hydrogen atom and hydrocarbon radicles, R3 is achain of at least three and not more than ten chain atoms linking thenitrogen-containing radicles and free from reactive radicles and X andX1 is each selected from the class consisting of oxygen and sulphuratoms, the amounts of the two compounds being such that the masscontains at most only a slight stoichiometric excess of amino groupsover the other reactive groups, heating being efiected at a temperatureof 200 to 250 C. for at least part of the reaction period and continueduntil a product having filament-forming properties is obtained.

6. Process for the production of linear polymers of high molecularweight, which comprises heating a reaction mass containing as solepolymer-forming reagents a diamine in which each of the amino radiclescontains at least one hydrogen atom directly attached to the nitrogenatom said amino radicles being the sole reactive radicles present in thediamine, and an organic compound having the formula 4 x.cx.:\'m.(oim,.xR1.c \..1\' 11; in where R1, R2, R3 and R4 is each selected from theclass consisting of hydrogen atom and hydrocarbon radicles, n is aninteger greater than 2 and smaller than 11 and X and X1 is each selectedfrom the class consisting of oxygen and sulphur atoms, the amounts ofthe two compounds being such that the mass contains at most only aslight stoichiometric excess of amino groups over the other reactivegroups, heating being effected at a temperature of 200 to 250 C. for atleast part of the reaction period and continued until a product havingfilament-forming properties is obtained.

7. Process for the production of linear polymers of high molecularweight, which comprises heating a reaction mass containing as solepolymar-forming reagents hexamethylene diamine and hexamethylene diurea,the molecular ratio of diurea to diamine being at least 1:1, heatingbeing eflected at -a temperature of 200 to 250 C. for at least part ofthe reaction period and continued until a product havingfilament-forming propertiesis obtained.

8. Process for the production of linear polymers of high molecularweight, which comprises heating a reaction mass wherein the solepolymerforming molecules present are molecules having the formula:

where R1, R3 and R4 is each selected from the class consisting ofhydrogen atom and hydrocarbon radicles, R2 is a divalent radicleconsisting of a chain of at least 5 and not more than 10 chain atomslinking the two nitrogen-containing radicles and X is selected from theclass consisting of oxygen and sulphur atoms, heating being continueduntil a product having film-forming properties is obtained.

9. Process for the production of linear polymers of high molecularweight, which comprises heating a reaction mass wherein the solepolymer-forming molecules present are molecules having the formula:

n u N.(CHI)n-NR2-CX.N

R1 R: where R1, R2 and R3 is each selected from the class consisting ofhydrogen atom and hydrocarbon radicles, n is an integer greater than 4and smaller than 11 and X is selected from the class consisting ofoxygen and sulphur atoms, heating being effected at a temperature of 200to 250 C. for at least part of the reaction period and continued until aproduct having filament-formin properties is obtained.

0. Linear polymers having film-forming properties and consistingsubstantially of units containing the group NR1.CX.NR2.CX1.NR3. whereR1, R2 and R3 is each selected from the class consisting of hydrogenatom and hydrocarbon radicles, and X and X1 is each selected from theclass consisting of oxygen and sulphur atoms.

11. Artificial filaments, foils and the like comprising a linear polymerhaving film-forming properties and consisting substantially of unitscontaining the group NR1.CX.NR2.CX1.NR5, where R1, R2 and R3 is eachselected from the class consisting of hydrogen atom and hydrocarbonradicles, and X and X1 is each selected from the class consisting ofoxygen and sulphur atoms HENRY DREYFUS.

